Tantrum cycles meltdown outburst first ride prototypes (9)

You may not know Brian Berthold’s name, but there’s a pretty good chance you’re familiar with some of his work. His most recent and well known design in the bike industry would have to be the Magic Link which was licensed to Kona, but his expertise goes back, way back. Before he ever got mixed up with bikes, Brian started on his path to suspension enlightenment through a motocross career which involved shock testing. That led him down the path of motorsports suspension and car design which included everything from rally, to Indy Car, and even a brief stint with F1.

Eventually, mountain bikes entered the picture with the formulation of Therapy Components and his first prototype air shock for Cannondale bikes in 1993. Production rear shocks for K2/Proflex paved the way to one of the first 7″ dual crown inverted suspension forks, and eventually into the world of floating brake calipers for World Cup DH racing for the likes of Trek and Kona, and ultimately back to Kona with the Magic Link suspension design. This is the abridged version, but rest assured, the guy’s got some history.

Why the long winded set up? That’s because Brian is back with his own company now with what he says is an even better suspension design…

For those unfamiliar with the Kona Magic Link bikes, essentially they used two shocks to create a system with variable travel and variable kinematics. In addition to the main shock like that on other bikes, there was a second smaller shock at the bottom which allowed the geometry, suspension rates, even travel numbers to change based on the bike’s positioning.




Tantrum cycles meltdown outburst first ride prototypes (3) Tantrum cycles meltdown outburst first ride prototypes (2)

Now, Brian says he has come up with an equally great suspension system – though without the additional weight and complexity of a second shock. Called the Missing Link, it relies on a linkage from the rear pivot behind the bottom bracket to the upper shock mount. The positioning of this link causes horizontal forces form pedaling or bumps to increase or reduce compression forces on the shock. I’ll stop trying to explain it here because Brian does a great job of breaking it down above.

You’d think with that much input on the suspension from the pedaling forces that the suspension would be completely stiff while climbing, but that’s one of the things that was so impressive about the bike. Thanks to the input from the rocker link above and the “buckling knee” tendency, the suspension remains surprisingly supple while climbing yet offers a supremely efficient climb.

Tantrum Cycles outburst meltdown first rides kickstarter

Tantrum Cycles outburst meltdown first rides kickstarter-2

Recently, I had a chance to ride both the 160mm travel Tantrum Meltdown 27.5″ and the 125mm travel Tantrum Outburst 29er at Brown County State Park, and I came away thoroughly impressed with both frames. The Missing Link suspension is sort of an enigma. It seems to have excellent small bump absorption, yet pedals and climbs way better than the travel should allow. Then point it down hill and it’s like it’s a completely different bike – in the best possible way. BCSP certainly has some technical sections and steady downhills, but I would never choose a 160mm travel bike for those trails, but with the Meltdown it was completely reasonable.

In fact, I’d go as far as saying the Meltdown may be one of the best climbing 160mm travel enduro bikes I’ve ridden. Brian attributes this to the fact that the geometry actually steepens by 3 degrees at the head tube and seat tube taking it from 66/73 to 69/76º all without any switches or fancy shocks.

It’s sort of mind boggling because the design carries with it all the suspension cliches that have become so commonly thrown around, only this actually works. Brian actually commented during our ride that he got frustrated that he built all these trick shocks that didn’t sell, so he decided that he would design a trick suspension that could use any shock on the market regardless of how simple it was.


While the basic design of the bike will remain unchanged for production, the geometry will see a few tweaks from the prototypes that I was able to ride. All of these should be welcome changes including shorter chainstays at 429mm (434mm for Outburst 29). The head tube angle also goes to 65 degrees for the Meltdown which sounds crazy slack for a bike like this, but you have to remember that the head tube angle steepens when climbing. The bike I was on at Brown County had an even slacker effective head tube angle since it was running an angle set, and I couldn’t believe how well it pedaled around tight sections of trail going up.

Tantrum cycles meltdown outburst first ride prototypes (4) Tantrum cycles meltdown outburst first ride prototypes (5)

Thanks to the modular dropout system, Brian is able to offer a number of configurations with fewer overall parts. That includes the Meltdown (27.5″ wheels, 160mm travel front and rear), Meltdown Race (Slacker, 180mm travel fork/160mm rear, 27.5″ wheels), Outburst (140mm fork/125mm rear, 29″ wheels), Outburst Race (150mm fork/125mm rear, 29″ wheels), Outburst XC (steeper geo, 29″ wheels, 125mm travel front and rear), and the wild Downburst with a 150mm travel fork and 29″ wheel up front and the 160mm travel rear with a 27.5″ wheel. This is supposedly all from the same frame just with different dropouts, rocker arms, shock, and shock mount.

Keeping with the times, the frames will feature Boost Spacing, but since the dropouts are replaceable, there are also 142mm dropouts available. Other details include a threaded 73mm bottom bracket, 31.6mm internal dropper compatible, room for a large water bottle in the frame, internal shift cable routing and external brake cable routing, and it’s even 2x drivetrain compatible. The aluminum frame isn’t the lightest at 7lb 9oz for a medium with an X Fusion rear shock, but after riding it I’d be willing to deal with the weight for the suspension’s performance. Hopefully this thing gets made in carbon one day, because that would be an awesome bike.


tantrum-bikeseurobike-2016-114 tantrum-bikeseurobike-2016-113

We’d love to spend more time on the bike to really get to know it, but for that to happen the first production run will have to be funded through Kickstarter. Brian has worked with other companies in the past, but this time he’s going it alone and hoping to have the bike produced himself, which is a pretty huge undertaking. Hence the Kickstarter. We caught up with him at Eurobike to see one of the newly painted prototypes which picked up its new look from Tantrum’s recent design competition. I’m digging the look – it’s different from a lot of the paint we see and is pretty subtle, though it has some interesting details.


Along with the Illusion Black, the frame will also be offered in Blueberry above. What may be most amazing about this bike is that over at Tantrum, it’s basically a one man show. Brian has done the design and development getting help where needed to build prototypes, but this project has evolved out of his home base in Indiana. Up for grabs on Kickstarter as we speak, the first 5 frames will sell for just $1200 which includes an X-Fusion O2 Pro RCX rear shock, though DVO Topaz rear shocks can be upgraded to for another $175. Complete bikes will also be offered, starting with their LowDough build kit at $2,600. If you get in on one of the earliest rewards, frames may be delivered as early as April 2017, just in time for next season!




    • Hi bikeshop. brian from Tantrum here. I wish it was licensed too! Ha. It will be, things in the works. but it’s really fun and cool to start my own brand.

      I like to remind myself of a man named Horst, who started a funky little bike company…..

    • Hi Watts, I do get little crap for the face, but most people realize it’s just for fun. I’m having fun with it. The face and the name are in honor of family life. Is anyone immune to a tantrum? I just take mine out on the trails….

    • Hi SatisFACTORY, lots of development in the future. but the bike reached a point where it was too good to mess with right now. I need to make them and work on future developments that are better, lighter, faster, stronger…..carbon???

  1. If it really does all the cliche things the review says, it will be a welcome addition to the mountain bike world. But what’s with bike names these days? Tantrum? Isn’t that something that 3 year old kids do? I guess all the good names are already taken…

  2. I would like to ride one, but a couple questions remain for me. First, the design has a huge number of pivots/moving parts all requiring bearings and/or bushings of some sort. These will still be subject to the same conditions that plague all suspension bikes including lateral forces and the elements. Thus, the maintenance on this rig will likely be high. Second, the suspension reaction to standard climbing/descending scenarios sound great, but I would like to know what the bike would do when sudden trials-esque moves are needed such as pedal kicks or track stands on a tricky downhill section. It would seem that having the head angle steepen suddenly in such a situation would make the bike a handful. Otherwise, it’s great to seem some unique thinking on mountain bike suspension as most designs have been around for awhile.

    • hi Hellbelly, Actually, the pivots and bearings in front of the seat tube help stiffness and reduce load and play on the most loaded bearings, namely those in the chainstay link. How and why? Think of the Missing Link as acting like a swinglink in other suspension designs. The swinglink is there to stiffen up the rear, even though it adds bearings. So the fact that the chainstay link is tied into the shock stiffens the whole assembly.

      BTW, I want to point out that the bikes Zach tested had a TON of miles, mag testing, etc. Beat up mules. I still haven’t replaced bearings.

      Your question on the pedal kicks is valid, but the reality is, unless you are traveling uphill, there isn’t enough resistance to your forward motion to steepen the geometry. It will be stiff, but not steepen.

  3. Sounds great !!! If I can get two kinds of dropouts+extra derrailleur link with the frame…take my money I want one pack !!!!

  4. So it has a couple extra bearings in the links. Worried about some wear and tear, get a fully rigid SS and ride on. All the bikes today are nothing more than a pile of expensive parts wearing out with every ride, a suspension pivot bearing being one of the cheapest of all the parts. And the Rocker ‘look’ is what it has to be, don’t like it don’t buy it but this is a case of engineering for function. What something that looks sexy on your rack or at the trailhead? get a Santa Cruz with shit suspension that looks simple and has acronyms. It is great to see someone like Brian thinking way outside the box and from the sounds of it, he kicked it out of the park. Zack and RC (PB) are professional testers who have extensive experience, for them to be saying the same thing about this bike in completely different terrain is pretty impressive.

  5. I’ve been very intrigued with this new design after following for awhile. BUT $2600 for an aluminum frame with an X-Fusion shock (per the Kickstarter page) that looks like that? With all due respect, but maybe Mr. Berthold should stick with engineering and let someone else (with licensing experience) handle the business. I always pull for the little guy and am doing so in this case.

      • Right in the Kickstarter description. Look at the frame options available at any price point… Each one says. “About $XXXX off MSRP”. So if you look at the “Pledge $1400 or more” option it says, “About $1200 off MSRP”. If you look at any of the frame options, all add up to $2600.

        • No you’re misreading his question. He’s asking where else you can find a full suspension bike with similar components for around $2600.

    • Hi Funky,

      The price is just the reality of limited low volume production. Molds have to be opened for all the tubes and forgings, so until you get into the thousands of units, it’s a little tougher. Plus, there are a couple extra links and parts in there.

      On the OTHER hand, you get performance that’s not available elsewhere at any price….so there is that…

    • Funky is correct, the MSRP is $2600 for the frame and fork. And that is at the higher end.

      It’s just a coincidence and a SMOKIN GOOD DEAL that the lowest cost complete on kickstarter is also $2600, which is $3400 MSRP.

    • Ummm, @Carl, ever designed a FS mtb much? That shock is there because that’s the way they get ti to do what they want it to do for the given suspension design. It’s not about looks, it’s about the way it works. That’s sort of like saying ‘move those struts on the Baja sand rail, because they don’t ‘look cool’ there’.

  6. I haven’t designed any more suspension systems than Carl, and I’m fine with form over function, but as soon as you throw multiple links into the equation there is more than one way to skin a cat. Yes, they all come with their own engineering trade-offs (strength, weight, stress), but there are multiple ways to achieve the same kinematics with different pivot placements and link configurations. Saying it can’t be made to function the same but look different just isn’t true.
    As far as this design, I don’t like the way the lower shock mount is inset into the down tube (those extra welds and hardware add weight, and where I ride the pocket would fill up with mud), but the ‘look’ of the shock position doesn’t bother me. The huge upper rocker is however disturbingly reminiscent of 1990’s Konas and Ellsworth.
    Would still love to ride one.

    • Hi Dylan,

      Of course you are correct. I ran several hundred iterations and that’s where I ended up when I got all of the characteristics where I wanted them. And if you move anything much, things go wonky in a hurry.

      The next step is not a version of this, but a complete, throw the links up in the air and start again with a completely different layout. I’m sure I’ll come up with something. But as I’ve mentioned, the bike just works too good right now not to be available as is. You can design things to perfection forever and never produce a thing. It’s kind of a trap.

      I claim the appearance will be come to known with superior suspension performance. (I could be wrong).

      The downtube shock location is unfortunate, but the DT is thick and adds stiffness.

      I’m working on a rubber boot for the hole, but I live in Indiana, which is pretty muddy and wet, it just doesn’t go there…not in the line of fire

      I do resent the 90’s rocker reference, however, not even half the size……


      • Thanks for replying Brian. The shock placement wouldn’t be a deal breaker, but nothing is out of the way when the puddles get deeper than the wheel axles…
        Hope production works out and they one day make it down under:)

        • thanks for the good words. We’re on our way.

          I’m gonna put some more thought into a rubber bootie cover thingy. In the meantime, at least there’s a drain hole in the bottom of the BB shell

  7. Hopefully a big company buys the design because, and I mean no disrespect, the name Tantrum will be the kiss of death. I know there was a contest for the new logo and color, but that original psychedelic fonts and colors had no where to go but up. As a rider and someone with years of marketing/PR/advertising/branding background I wish you the best.

    • Hi Dan,

      Obviously, i hope you’re wrong. I hate naming things. We tested thousands. Everyone hates something. Tantrum actually got an overwhelmingly favorable response. Most people just seem to appreciate the fun.

      thanks for the input and good thoughts…

  8. Very nice suspension design. It makes sense to me even if I’m not an “engineer”. Looking forward to easier availability. Nice work, Brian. A rider from across the Pacific, here. I hope I can get to my grubby mitts on one of your bikes in the future.

  9. Brian! Hey man, this is the second or third time now I’ve come across an article about Tantrum Cycles, and it’s been cool to see the process–the evolution of your ideas and watching them grow into a company. I do hope bike companies license it and/or even improve upon it a bit, it looks to really have some merit. I like what you’re doing with the suspension design, I want to send you some stoke!

    On a different note, I LOVE that shirt you’re wearing in these photos… are they available for purchase? It would be a great one to wear at the shop, and I like supporting the guys out there going for it. [For what it’s worth, I think Tantrum is a fine name, though I do look forward to the day that you can shift some focus to font style/frame colors 😉 ]

      • YES! Thanks Brian. I’ll order one tomorrow then. Cool stuff.

        I know you caught some heat for the logo design contest you put forth, and I understand the issue from the professional point of view. However, as a ‘hobby’ designer, I’d be stoked to be able to design my own stuff. Or, be more than happy to contribute to pool of ideas for you. mikealive @ gmail if you would be so kind as to provide me some design parameters (size, available colors/amount of colors per logo, etc) Thanks dude!

        • Ha, I first read this and thought you meant a BIKE!!!. That’s ok, I’ll be happy to sell a shirt too.

          We’re gonna stick with subtle variations on the contest winning graphic for now. but I was wondering, if customers could design a sticker when ordering the bike………

  10. I would love a carbon version with a remote lock out fork. Truthfully, I never liked the look of an Ellsworth, but always figured, they were fugly, for a reason. That rear rocker, vs. the swoopy diagonal and front to back looks of FSR or VPP links.
    My park is either up or down, so a stiff system climbing the trail and and a buttery and generous feel downhill, would hit the spot!

  11. Brian,
    I remember meeting you at Interbike with an early prototype under a different name a few years ago. The idea blew me away back then, and I’m stoked that you’re getting it to market! Keep up the good work!

    Also your links look a lot more refined now, despite being a bit less brightly colored 🙂

  12. Hi Brian,
    Looks great, I’m intrigued and very interested, I’ll definitively take a look at it on the kickstarter site. 🙂
    A couple of questions from my other interests in life – manufacturing. 🙂
    The frame itself is welded aluminum – correct?
    What about the links, dropouts, etc., – are they forged, or have you 3d-printed them?

    • Thank you Frippolini, The frame is 6061, although we may use 6069 for production.

      All the links are CNC on the samples, but will be 3d cold forged in production. I think I’m still a little afraid of 3d printing for those.

  13. They always say to buy a bike for the type of riding that you do! Since I have always found myself at home on a single speed 29er and there not being any significant climbs in my area, that is what I enjoy most… After all that drivel, is there a way to design this into a single speed frame that does not need a tensioning device? Something like that would get me off of a hardtail.

    • I’m not Brian, but I can’t see this design ever being able to go SS without a tensioning device of some sort, but that’s the case for 90ish% if FS bikes out there. If you really want FS SS… then go look at Lenz Sport. They have two models: Milkmoney and Lunchmoney that do what you are asking for, I cannot speak for those models, but my wife loves her Lenz (a different model with a different design, granted).

    • 2 x is possible.

      In some of the videos, I show the suspension moving to forces so you can see what’s going on a little better. This one in particular, I think shows fairly clearly.

  14. Really cool design! Great job figuring it out. It does kind of remind me of the GT I-drive/Mongoose Freedrive/Schwinn varient (cant find their name). I had an early Teocali, and found it performed in a similar way.

    This looks like it would work even better though. Guess I better think about getting back on the trails!

    • hi Rampa, thanks so so much. I can’t remember the last time I rode an I-drive bike, but doesn’t the BB move with the suspension?

      I think you’d find this a massive improvement

  15. I have an older(Coil-Air)mtb and see the slight mechanical similarity, there is a benefit to a suspension formula that adjusts and accommodates to the riders needs during riding.
    I am glad people like Brian exist in the industry…small ideas to better the whole experience and new concepts to push the experience forward.
    Thanks Brian.

COMMENT HERE: (For best results, log in through Wordpress or your social media account. Anonymous/fake email comments may be unapproved or deleted. ALL first-time commenter's posts are held for moderation. Check our Comment Policy for full details.)

This site uses Akismet to reduce spam. Learn how your comment data is processed.